This invention relates to adaptation of CSMA/CD-type networks, and particularly Ethernet to long-distance communication, and specifically for metropolitan area networking. Standard Ethernet type communication (IEEE/ANSI Standard 802.3) is intended primarily for local data communication, typically over lines less than 1800 meters (1.1 miles) in radius. Ethernet employs carrier sense multiple access/carrier detection (CSMA/CD) protocols. Such protocols under 802.3 require a baseband carrier signal in order to permit the sensing of the presence or absence of collisions among potentially-interfering signals. The protocols also specify that nodes must be able to communicate within a defined time short interval, which limits the radius of communication to relatively short ranges.
Bridges and routers are known for redirecting signals originating or terminating in an Ethernet node through various other media, including broad-band and narrow-band links. Such links may be either speed-limited or distance-limited, or they may require substantial protocol conversion. Specifically, it is considered desirable to keep the MAC CSMA/CD layer of Ethernet intact to the extent possible.
A line of telephone central office bypass digital network communication products is available from the assignee of the present invention, First Pacific Networks of Sunnyvale, Calif. (FPN), which supports high-speed, metropolitan-area digital communication. Heretofore no bridge has been provided which can be used as an interface between conventional Ethernet nodes via the FPN network.
What is needed is a mechanism for extending a local area network to a substantially greater range, e.g., in the metropolitan area range of 50 km to 100 km in radius, without degradation in speed or response time.